Converts an OCaml number to a canonical integer literal of type :real.

DESCRIPTION

The call mk_realintconst n where n is an OCaml number (type num) produces
the canonical literal of type :real representing the integer n. This will
be of the form `&m' for a numeral m (when n is nonnegative) or `-- &m'
for a nonzero numeral m (when n is negative).

FAILURE CONDITIONS

Fails if applied to a number that is not an integer (type num also includes
rational numbers).